ネットワーク遅延
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端末時刻診断
時計ずれテスト
Compare your device clock with network-calibrated atomic time. Use the offset, delay, and accuracy estimate to decide whether your computer needs a time sync check.
端末時計のずれ
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校正中○ 同期中
Measuring network delay and comparing your device clock with calibrated time.
推定精度
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最終同期
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What It Means
Positive offset means calibrated time is ahead of your device clock. Negative offset means your device clock is ahead.
ライブ比較
- 端末時刻
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- 原子時刻
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診断レポート
Copy this report when troubleshooting login, certificate, logging, or distributed-system time issues.
Time.ms 時計ずれレポート
Under 100 ms
Usually excellent for browser, logging, and most user-facing workflows.
Over 1 second
Worth checking automatic time sync, VPN behavior, VM host time, or system time settings.
Over 1 minute
Can break authentication, certificates, scheduled jobs, and audit trails.
Related Time Tools
After checking drift, convert timestamps, inspect UTC, or use the NTP setup guide to correct system time.
時計ずれ FAQ
What is clock drift?
Clock drift is the difference between your device clock and a more reliable time reference.
What offset is acceptable?
A few hundred milliseconds is usually fine for browsing, while authentication and distributed systems often need tighter alignment.
How does this test estimate accuracy?
Time.ms measures network round-trip delay and uses half that delay plus a small browser timing allowance.